Time Duration Calculator

1. Calculate duration: Enter a start time and end time using the time pickers. The result shows hours and minutes, total minutes, and decimal hours. If your shift crosses midnight (for example, 10:00 PM to 6:00 AM), check the overnight toggle.
2. Add or subtract time: Enter a starting time, choose whether to add or subtract, and enter the hours and minutes. This is useful for finding out what time a meeting ends, when to take a break, or when something will be ready.

Duration is calculated by converting both times to total minutes and finding the difference:

Start time in minutes = start hours × 60 + start minutes
End time in minutes   = end hours × 60 + end minutes
Duration in minutes   = end - start

For overnight shifts:
Duration = (end + 24×60) - start  (when end < start)

Example: Start 9:00 AM, End 5:30 PM:

Start = 9 × 60 + 0  = 540 minutes
End   = 17 × 60 + 30 = 1050 minutes
Duration = 1050 - 540 = 510 minutes = 8h 30m

Decimal hours (used in payroll) = total minutes / 60:

510 / 60 = 8.5 decimal hours

Common decimal conversions: 15 min = 0.25 hr, 30 min = 0.5 hr, 45 min = 0.75 hr.